Single Carrier-Frequency Division Multiple Access (SC-FDMA) is employed as an uplink multiple access scheme in the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) standard (e.g. release 8 or 9). Introduction of clustered Discrete Fourier Transform-spread-Orthogonal Frequency Division Multiplexing (DFT-s-OFDMA) as an uplink multiple access scheme is under discussion in the 3GPP LTE-Advanced (LTE-A) standard (e.g. release 10) being an evolution of the 3GPP LTE standard. Uplink/downlink transmission in a single carrier band is supported in the 3GPP LTE standard and uplink transmission through a plurality of carriers (i.e. carrier aggregation) is under discussion in the 3GPP LTE-A standard. In addition, while the 3GPP LTE standard support uplink transmission from a User Equipment (UE) through a single Transmission (Tx) antenna, the 3GPP LTE-A standard discusses support of uplink transmission from a UE through a plurality of Tx antennas (uplink multi-antenna transmission) in order to increase uplink transmission throughput.
Multi-antenna transmission is also called Multiple Input Multiple Output (MIMO). MIMO can increase the efficiency of data transmission and reception using multiple Tx antennas and multiple Reception (Rx) antennas. MIMO schemes include spatial multiplexing, transmit diversity, beamforming, etc. A MIMO channel matrix formed according to the number of Rx antennas and the number of Tx antennas can be decomposed of a plurality of independent channels and each independent channel is called a layer or a stream. The number of layers or streams or a spatial multiplexing rate is called a rank.
A multi-transmission stream or multi-layer transmission scheme may be applied to a UE for the purpose of spatial multiplexing, as an uplink multi-antenna transmission technology. This scheme is called Single User-MIMO (SU-MIMO). To maximize the capacity of a transmission channel in uplink SU-MIMO, a precoding weight may be used. This may be referred to as precoded spatial multiplexing.